Liquorix Drops Kernel 7.1-9, Pushes Project-C Scheduler Toward Mainline Parity
Another Liquorix kernel update hit the public repositories. The new point release skips fresh base kernel merges in favor of a dedicated stability sweep for Project-C, the custom in-kernel scheduler that now defines the project.
If you followed the Zen Kernel era, you probably remember the PDS and BMQ schedulers that originally gave Liquorix its twitchy desktop feel. Steven Barrett has spent the last two years rebuilding that entire piece of the kernel from scratch. Project-C lives under sched/alt as CONFIG_SCHED_ALT, meaning it compiles directly into the kernel tree rather than leaning on out-of-tree modules. The goal has always been to keep Liquorix’s famously low frame-time deviations while finally letting upstream scheduler improvements flow in without constant patching.
The 7.1-9 tag brings that philosophy to the forefront. Out of roughly eleven patches in the changelog, eight are direct upstream syncs. You get runtime accounting unification across scheduler classes, a restructured struct rq for better cache locality, and PSI accounting pulled off the update_rq_clock_task() hot path. Those are the kind of changes that sound dry on paper but matter when you’re trying to squeeze consistent framerates out of a hybrid CPU at midnight.
Barrett also folded in a handful of Liquorix-specific tweaks. Lockdep assertions now enforce correct locking discipline at scheduler change boundaries. The LATENCY_WARN feature gets disabled by default, which finally cuts the kernel log spam that used to flood dmesg during normal desktop loads. There’s also a fix for ENQUEUE_HEAD behavior during scheduler changes and proper tagging for migrated task wakeups. It’s a solid consolidation. Keep in mind that this is the third point release in the 7.1 series, and the pattern is clear: the maintainer is trading flashy feature drops for hardening work.
The 7.1-9.1 packaging bump landed at 18:38 UTC on the same day, suggesting Barrett wanted build quirks sorted immediately. Custom kernel projects like this always walk a fine line between bleeding-edge tuning and breaking your system on a Tuesday afternoon. Six months into Project-C development, that line is finally stabilizing.
The Hardware Reality Check
Here’s where you should temper expectations. Liquorix has never been a stability showcase for mainstream hardware. Several open GitHub issues point to hard freezes and soft lockups tied to AMDGPU, particularly on the Ryzen 5500U and during gaming workloads. Issue #225 explicitly notes a stock Debian 6.12.94 kernel running Beyond All Reason without a hiccup while Liquorix drops a console. However, at the same time, those freezes have been a recurring theme since the 7.0 cycle, and it’s worth assuming Project-C’s tighter locking model might be exposing edge cases in the AMDGPU driver. If you buy a fresh GPU or run a recent Ryzen APU, you might want to hold off on 7.1-9 until the maintainer closes out a few of those regression tickets.
Getting the kernel is straightforward. The official install script pulls Debian, Ubuntu, and Arch builds:
bashcurl -s 'https://liquorix.net/install-liquorix.sh' | sudo bash
Ubuntu users can also grab it from the ppa:damentz/liquorix PPA, which typically ships within hours of the Debian upload. Arch users should grab linux-lqx from the AUR. The package only ships for AMD64, so if you’re running ARM or RISC-V, this one passes you by.
Head here to watch the GitHub issue tracker if you plan to roll it out on an integrated graphics setup. Liquorix 7.1-9 is a maintenance release, but a necessary one. The heavy lifting here is about keeping Project-C from drifting into the weeds while upstream kernel developers ship their own scheduler improvements. It’s arguably the most ambitious in-kernel alternative scheduler effort from an independent maintainer right now, though the AMDGPU regression pile means it’s not ready for your main workstation just yet.
